I've said before – I think it was a huge mistake in the storytelling to have Venat keep her memories and act on them, carrying out her plan "because the time-traveller said so".

She should have been memory-wiped with the others and later objected to Zodiark for independent reasons, perceiving some kind of design flaw that called for the creation of Hydaelyn to address it.

If lost memories are regained upon death and return to the aetherial sea, then she could still regain those memories upon becoming Hydaelyn and retreating to the sea.